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Obesity

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Obesity

Obesity has become a pandemic in itself, according to some scientists, with about 1.9 billion people worldwide overweight and at least 650 million obese in 2016, according to the World Health Organisation. That's a significant portion of the population with an obesity problem. Cardiovascular disease is becoming or already is the leading cause of death in many countries. We can begin to understand why obesity is a major cause for concern.

Obesity Obese person StudySmarterAn obese person, Flaticon

What is obesity?

Obesity is a condition in which a person is identified as overweight with an accumulation of body fat. Excess body weight, typically 20% or more above a person's ideal body weight, may indicate obesity.

Obesity can lead to an increased risk of disease, disability, or in certain cases, death. Obesity can be the result of a poor diet, lack of physical activity, or an underlying disease. Sometimes all of these factors can be present at the same time. When you eat more calories than you burn, you begin to gain weight. If this is the case over a long time, it will eventually lead to significant weight gain.So what are the possible problems that an overweight person can face?

What are the side effects of obesity?

Obesity puts a significant strain on the body, and your organs have to work extra hard to do what they need to do.

  • Some side effects of this are:

  • Physical health problems.

  • Mental illness.

  • Low energy.

  • Lower self-esteem and self-confidence.

  • Difficulties at work.

  • Difficulties in personal relationships.

  • Difficulties with travel.

  • Difficulties in performing physical activities.

As mentioned earlier, cardiovascular diseases (such as heart disease and stroke) are one of the main risk factors for high BMI (body mass index). In 2012, they were the leading cause of death, according to WHO.

What is morbid obesity?

Morbid obesity may also be referred to as severe obesity.

Morbid obesity is a condition in which the calculated BMI is greater than 35 and is associated with at least one medical condition.

It is important to know that BMI is not infallible. When a muscular person, such as a bodybuilder or someone who goes to the gym, gets their BMI results, it would not be surprising if they were classified as obese. This is because BMI is simply a measurement tool that does not accurately indicate fat percentage and does not take muscle into account.

Morbid obesity can affect bodily functions and be associated with serious health problems, such as:

  • Hypertension.

  • Type 2 diabetes.

  • Sleep apnea.

  • Heart disease.

  • Stroke.

  • Reproductive problems.

  • Gallstones.

  • Cancer.

Obesity Heart disease StudySmarterObesity may lead to heart disease, Flaticon

Obesity in the UK

It is estimated that 1 in 4 adults in the UK is obese. A 2017 study by the European Society of Cardiology estimated that British adults are less physically active, consume less fruit and vegetables, and greater amounts of sugar compared with other European countries.

What are the causes of obesity?

Several factors can lead to obesity. In the following, we will look at the general causes of obesity, followed by medical, biological, and psychological causes.

Lack of physical activity

Lack of physical activity can lead to obesity because energy from food is stored as fat because it is not used. The Department of Health and Human Services recommends that adults engage in at least 150 minutes of physical activity per week, such as walking, running, or bicycling, and this time can be spread out over the week, such as in 30-minute sessions 5 days per week.

Poor diet

Foods high in fat and sugar can lead to excess weight being stored. Such examples include:

  • Processed food.

  • Fast food.

  • Sugary drinks.

  • Alcoholic drinks.

Biological explanations of obesity

There are several biological reasons that may explain an increased likelihood of obesity. These medical reasons include genetics, hormones, medications, appetite control, and other physical health conditions.

Genetics

Certain genetic traits can make it harder for a person to lose weight or make them more prone to gaining weight.

In rare cases, genetic conditions such as Prader-Willi syndrome can lead to obesity, as overeating is strongly associated with this condition.

In addition, Frayling et al. (2007) identified a gene associated with fat mass and obesity. This gene is also known as the FTO gene. It was found that people with two copies of this gene have a 70% increased risk of obesity.

Even though genetic traits can make it difficult to lose weight, this does not mean that it makes it impossible to lose weight.

Stunkard et al. (1986) found that when obesity rates in Danish adopted children were compared with those of their biological parents and those of their adoptive parents, there was a strong relationship between the biological cases. There was no relationship between adopted children and their adoptive parents, suggesting genetics plays a role in weight management in adulthood.

Genetic arguments, like all biological arguments, have a problem with reductionism that you should consider when using studies like this. We also need to consider how generalisable the results are, as one country's results may not reflect another country's results.

Evolutionary explanation

Neel (1962) proposed an evolutionary explanation for obesity that is related to the genetic explanation of obesity. This explanation is called the 'thrifty gene hypothesis’. He proposed that our ancestors ate large amounts of food, including fatty and sugary foods, to store energy and ensure survival.

When food supplies were scarce, those who were able to store body fat were more likely to survive and pass on their genes.

In modern times we no longer face such shortages and eating too much leads to weight problems.

Obesity Theory of evolution StudySmarterTheory of evolution, Flaticon

What medications are linked to obesity?

Certain medications have been linked to weight gain:

  • Anti-depressants.

  • High blood pressure medication.

  • Seizure medication.

  • Steroids.

Appetite control issues in obesity

Ghrelin and leptin are hormones involved in the control of eating behaviour.

Leptin typically helps mediate long-term energy balance mechanisms and suppresses the urge to eat. It indicates that you are full. Ghrelin acts faster than leptin and triggers feelings of hunger.

Studies such as that by Klok et al. (2007) have found that obese patients may be leptin resistant. Obese people tend to have high leptin levels and are resistant to exogenous sources of leptin (as many originally thought leptin would reduce feelings of hunger and be a possible treatment plan for obese people).

It appears leptin cannot fully exert its effects in obese people and therefore they have difficulty achieving a feeling of fullness, which may be associated with overeating.

What are the neural explanations of obesity?

The hypothalamus ultimately controls eating behaviour, as we discussed in our article on controlling Eating Behaviours. The ventromedial hypothalamus (VMH) is involved in food regulation and tells you to stop eating when hormones indicate you are full.

Dysfunction of the VMH can lead to obesity, as studies have shown lesions in this area can lead to overeating and problems regulating food intake.

What are the psychological explanations of obesity?

Psychological explanations for obesity examine how various mental health, environmental, and social factors can lead to obesity. Psychological explanations for obesity may also be closely linked to biological explanations for obesity.

The boundary model

Herman and Polivy (1983) developed the boundary model. It assumes that certain parameters psychologically explain a person's desire to eat and the associated biological pressures.

  1. There is a biological process behind man's need and desire for food.

  2. Hunger causes one to eat the minimum amount of food needed to survive. When you eat this food, a feeling of satiety eventually sets in, signalling you to stop eating.

  3. Your environment influences the span between hunger and satiety.

Overall, the boundary model is represented as a scale between hunger and satiety. There is a minimum (hunger) and a maximum (satiety). In obesity, problems arise when the range is not maintained, and this is where restraint theory comes into play.

Restraint theory

If you have ever dieted or dealt with people who have dieted, you may have seen this phenomenon in action or even experienced it yourself.

Restraint theory states that when you try to restrict or stop eating, you end up eating more than if you did not. This is due to a cognitive boundary that dieters have introduced that, when crossed, causes a state of disinhibition regardless of where you are on the hunger/satiety scale.

Restrained eating is based on the understanding that you will not exceed this self-imposed cognitive dietary limit. Exceeding this limit leads to disinhibition, where the dieter basically gives up and decides to eat without restriction because there is no longer any point in trying. This can go beyond satiety, allowing them to eat more despite being full.

Dieters may also lose the ability to recognise their own body's signals to start and stop eating. If restrained eaters constantly exceed their satiety limit, they may become obese.

Obesity Restraint Theory binge eating resulting in weight gain StudySmarterBinge eating resulting in weight gain, Flaticon

Mental health explanations

Mental health conditions can lead to various symptoms, such as increased appetite, sleep problems, decreased energy, disruption of hormone levels, and decreased activity, which can contribute to weight gain and obesity. Poor problem-solving skills are also associated with an inability to keep track of eating and to refrain from overeating.

Such mental health issues and conditions include:

  • DepressionDepression can lead to obesity or occur as a result of obesity. Factors such as low mood, loneliness, decreased activity, decreased self-confidence, sleep disturbances, and low self-esteem can trigger stress and biological responses that lead to weight gain and obesity.

  • Stress Stress can affect eating behaviours. For some people, stress can cause them to consume fewer calories. For others, stress can lead to increased appetite, consumption of high-calorie foods, and sleep disturbances. Stress also disrupts hormone balance, affecting leptin, cortisol and other hormones that are also associated with weight gain and obesity.

  • Anxiety – Anxiety can affect stress levels, causing a person's body to respond and be more prone to weight gain and obesity.

  • Eating disorders – In binge eating, a person suddenly eats excessive amounts of food, especially high-calorie food. Binge eating can lead to obesity. Binge eating is also associated with bulimia, which involves binge eating followed by vomiting. People with bulimia may also develop obesity. Factors that can lead to binge eating or bulimia include body dissatisfaction, low self-esteem, stress eating, loneliness, shame, and depression.

Other psychological explanations can also consider:

  • Social factors such as learned behaviours from family members and cultural norms.

  • Environmental factors such as financial income, making higher calorie foods cheaper and more readily available.

Obesity - Key takeaways

  • Obesity is a condition in which a person is identified as overweight with an accumulation of body fat. Excess body weight, typically 20% or more above a person's ideal body weight, may indicate obesity.
  • According to some scientists, obesity has become a veritable pandemic. According to the World Health Organisation (WHO), about 1.9 billion people worldwide were overweight and at least 650 million were obese in 2016.
  • When you eat more calories than you burn, you begin to gain weight. If this is the case over a long time, it will eventually lead to significant weight gain.
  • Side effects of obesity include physical illness, such as cardiovascular diseases (one of the leading causes of death in many countries), mental illness, low energy and low self-esteem, inability to perform everyday tasks, and problems getting around, to name a few.
  • Morbid obesity can affect bodily functions and be associated with serious health problems such as hypertension, type 2 diabetes, sleep apnea, heart disease, stroke, reproductive problems, and many other conditions.
  • Biological explanations for obesity include genetic predisposition (FTO gene), biological links between family members, evolutionary origins, problems with medications, and appetite problems (ghrelin and leptin).
  • Psychological explanations include the boundary model (a scale between hunger and satiety) and the restraint theory, according to which dieters eat more (sometimes beyond satiety levels) when they exceed their cognitive diet boundary. Mental illness can also affect obesity, as some problems are exacerbated and food can become a source of comfort.

Frequently Asked Questions about Obesity

Hormones are one of the biological reasons that can explain an increased likelihood of obesity. Ghrelin and leptin are hormones involved in controlling eating behaviour. 

For example, stress can disrupt hormone levels, affecting leptin, cortisol and other hormones which have also been linked to weight gain and obesity. 

Obesity is a condition in which a person is identified as overweight with an accumulation of body fat. Obesity has become a pandemic in itself, according to some scientists, with about 1.9 billion people worldwide overweight and at least 650 million obese in 2016, according to the World Health Organisation.

Excess body weight, typically 20% or more above a person's ideal body weight, may indicate obesity.

Final Obesity Quiz

Question

One in four adults in the UK is estimated to be obese. True or false?

Show answer

Answer

True. One in 4 adults is estimated to be obese.

Show question

Question

Name one side effect of obesity.

Show answer

Answer

  • Physical health-related conditions.
  • Mental health-related conditions.
  • Low energy.
  • Self-esteem & confidence.

Show question

Question

Morbid obesity can also be referred to as _____.

Show answer

Answer

Severe obesity.

Show question

Question

How much exercise is recommended to carry out each week?

Show answer

Answer

150 minutes.

Show question

Question

Morbid obesity is linked to health conditions such as ear infections. True or false?

Show answer

Answer

False. Morbid obesity is linked to health conditions such as high blood pressure, cancer, heart disease and other related severe health conditions.

Show question

Question

Psychological explanations of obesity are linked to biological explanations of obesity. True or false?

Show answer

Answer

True. Psychological and biological explanations are linked with each other. Psychological effects can impact biological responses.

Show question

Question

What BMI score is considered severely obese?

Show answer

Answer

40 +.

Show question

Question

List the name of a genetic explanation that has been linked to obesity? 

Show answer

Answer

Prader Willi syndrome, FTO gene, thrifty gene hypothesis.

Show question

Question

List the name of a genetic explanation that has been linked to obesity.

Show answer

Answer

Prader Willi syndrome, FTO gene, thrifty gene hypothesis.

Show question

Question

List two types of unhealthy food or drinks that can result in weight gain. 

Show answer

Answer

Processed foods, fast food, sugary drinks, alcoholic drinks.

Show question

Question

What does BMI stand for?

Show answer

Answer

Body mass index.

Show question

Question

List three ways in which we can prevent obesity. 

Show answer

Answer

A balanced diet, regular exercise, relaxation, sleep, medical support.

Show question

Question

Name a medication linked to weight gain and obesity. 

Show answer

Answer

Antidepressants, high blood pressure medication, seizure medication and steroids.

Show question

Question

Name a hormone that can lead to obesity.

Show answer

Answer

Leptin, cortisol, hypothyroidism.

Show question

Question

List one mental health condition that can be linked to obesity.

Show answer

Answer

Depression, anxiety, stress, eating disorders.

Show question

Question

Neel thought our ancestors ate large quantities of food to support ______.

Show answer

Answer

Survival.

Show question

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